Showing 6 results for Numerical Analysis
A. Rahmani Firoozjaee, M.h. Afshar,
Volume 5, Issue 2 (6-2007)
Abstract
A meshless method namely, discrete least square method (DLSM), is presented in the
paper for the solution of free surface seepage problem. In this method computational domain is
discredited by some nodes and then the set of simultaneous equations are built using moving least
square (MLS) shape functions and least square technique. The proposed method does not need any
background mesh therefore it is a truly meshless method. Several numerical two dimensional
examples of Poisson partial differential equations (PDEs) are presented to illustrate the
performance of the present DLSM. And finally a free surface seepage problem in a porous media is
solved and results are presented.
Kourosh Shahverdiani, Ali Reza Rahai, Faramarz Khoshnoudian,
Volume 6, Issue 2 (6-2008)
Abstract
Large capacity cylindrical tanks are used to store a variety of liquids. Their Satisfactory
performance during earthquake is crucial for modern facilities. In present paper, the behavior of cylindrical
concrete tanks under harmonic excitation is studied using the finite element method. Liquid sloshing, liquid
viscosity and wall flexibility are considered and additionally excitation frequency, liquid level and tank
geometry is investigated. The results show a value for wall thickness to tank diameter ratio which may be used
as a guide in the consideration of wall flexibility effects.
Ali Kavand, S.mohsen Haeri, Arian Asefzadeh, Iraj Rahmani, Abbas Ghalandarzadeh, Ali Bakhshi,
Volume 12, Issue 3 (7-2014)
Abstract
In this paper, different aspects of the behavior of 2×2 pile groups under liquefaction-induced lateral spreading in a
3-layer soil profile is investigated using large scale 1-g shake table test. Different parameters of the response of soil and piles including time-histories of accelerations, pore water pressures, displacements and bending moments are presented and discussed in the paper. In addition, distribution of lateral forces due to lateral spreading on individual piles of the groups is investigated in detail. The results show that total lateral forces on the piles are influenced by the shadow effect as well as the superstructure mass attached to the pile cap. It was also found that lateral forces exerted on the piles in the lower half of the liquefied layer are significantly larger than those recommended by the design code. Based on the numerical analyses performed, it is shown that the displacement based method is more capable of predicting the pile group behavior in this experiment comparing to the force based method provided that the model parameters are tuned.
M. Derakhshandi, H. R. Pourbagherian, M. H. Baziar, N. Shariatmadari, A. H. Sadeghpour,
Volume 12, Issue 4 (12-2014)
Abstract
In this study, the mechanical behavior of Vanyar dam was evaluated at the end of construction. A two-dimensional numerical analysis was conducted based on a finite element method on the largest cross-section of the dam. The data recorded by the instruments located in the largest cross-section were compared with the results of the numerical analysis at the place of instruments. The settlement, pore water pressure, and total vertical stress were the parameters used for evaluating the dam behavior at the end of construction. The results showed that the settlements obtained from the numerical analysis were in reasonable agreement with the data recorded by the instruments, which proved that the numerical analysis was implemented based on realistic material properties. In addition, the difference between the instruments and the numerical analysis in terms of total vertical stresses was discussed by focusing on the local arching around the pressure cells. Furthermore, the arching ratios were calculated based on the results of the numerical analysis and the data recorded by the instruments. Moreover, the pore water pressures and total vertical stresses, recorded by piezometers and pressure cells, respectively, were the two parameters utilized for evaluating the hydraulic fracturing phenomena in the core. The results demonstrated that the maximum settlement obtained from the numerical analysis was 1 m, which corresponded to 46 m above the bedrock on the core axis. The recorded data in the core axis indicated that maximum settlement of 0.83 m happened 40 m above the bedrock. In addition, maximum pore water pressure ratio recorded by the instruments (Ru =0.43) was more than that obtained from the numerical analysis (Ru =0.26) this difference was due to the local arching around the pressure cells. Furthermore, the arching ratios in Vanyar dam were found to be 0.83 to 0.90. In general, the results revealed that the dam was located on a safe side in terms of critical parameters, including settlement and hydraulic fracturing. In addition, results of the numerical analysis were consistent with those provided by the monitoring system
Dr. Gh. Tavakoli Mehrjardi, Prof. S.n. Moghaddas Tafreshi, Dr. A.r. Dawson,
Volume 13, Issue 2 (6-2015)
Abstract
A numerical simulation of laboratory model tests was carried out to develop an understanding of the behaviour of pipes in a trench prepared with 3-Dimensional reinforced (namely "geocell-reinforced" in the present study) sand and rubber-soil mixtures, under repeated loadings. The study reports overall performance of buried pipes in different conditions of pipe-trench installations and the influence of pipe stiffness on backfill settlements, stress distribution in the trench depth and stress distribution along the pipe's longitudinal axis. Good agreements between the numerical results and experimental results were observed. The results demonstrate that combined use of the geocell layer and rubber-soil mixture can reduce soil surface settlement and pipe deflection and eventually provide a secure condition for buried pipe even under strong repeated loads.
E. Kozem Šilih, M. Premrov, M. Kuhta, S. Šilih,
Volume 13, Issue 4 (12-2015)
Abstract
The paper presents a parametric numerical study on the horizontal load-bearing capacitiy of timber framed wall elements coated with single fibre plaster boards (FPB) that can be used in the construction of single- or multi-storey prefabricated buildings. The research deals with both the full elements (without any opening) and with elements containing an opening. The key behaviour indicators like the racking stiffness and strength were determined and presented as ratios dependent on the opening area. A comparative study has proved that none of the methods from the literature that were previously developed for different types of wall elements can be accurately applied to the FPB-sheated panels. It has also been shown that the methods currently available in the European design codes underestimate the capacity of wall elements with openings. Based on the results some diagrams are proposed that enable quick and efficient determination of the essential properties of wall elements with arbitrary areas of openings and may thus represent a useful tool for the structural design process.